In this work, we propose a plasmonic absorber structure based on planar thin films metal-dielectric layers, and PCMs (Phase Change Materials) in the infrared spectrum, between 1000-2200 nm, which has high optical contrast in these regions, thus favoring its use. The transition effects between the intermediate to amorphous and crystalline phases of the PCMs layers are analyzed, based on the Lorentz-Lorenz relation. Absorption effects can be controlled using functions in which geometric parameters and crystallization levels can be related. The results presented show high absorption above 95% in both phases of the material, in normal incidence. We also analyzed the structure in oblique incidence in the TE and TM polarization modes. These structures are eligible for next-generation reconfigurable control devices.
In this work, we propose a plasmonic absorber structure composed of periodic gratings with hexagonal arrangements aided by rectangular metal-dielectric layers and PCM's (Phase Change Materials) in the infrared spectrum, between 1200-6000 nm, which has high optical contrast in these regions, thus favoring its use. The transition effects between the intermediate to amorphous and crystalline phases of the PCMs layers are analyzed, based on the LorentzLorenz relationship. Absorption effects can be controlled using functions in which geometric parameters and crystallization levels can be related. The results presented show high absorption above 95% in both phases of the material, in normal incidence. The physical mechanisms of absorption confinement were also investigated. These structures can offer great light coupling advantage in reconfigurable nanoplasmonic devices.
We analyzed and proposed a planar plasmonic absorber based on a tri-layer nanorressonators structure using metal-PCM's-metal. The planar absorber uses resonance between the metal and dielectric layers, for maximum light absorption in the infrared (1000 – 2200nm) electromagnetic spectrum. The resonance peak of the absorber can be shifted to other regions of the spectrum by varying the phase (amorphous and crystalline) of the dielectric film. It is also possible to control the absorption with the angle of incidence in the TE and TM polarization modes. The high absorption and high tolerance for fabrication errors of the absorber proposed can be exploited in a large number of optoelectronic devices.
We propose in this work a structure 3-D plasmonic absorber composed of metal-dielectric and ultrathin film layer of PCM's (Phase Changed Materials). The geometric parameters of the structure proposed were optimized to exhibits strong absorption for normal incidence. The effects of the phase change from PCM's are analyzed and it is possible to observe a shift in the resonant peaks of absorption when the phase changes from amorphous to crystalline. The geometrical parameters of the structure were analyzed so that the absorption peak was syntonized. Also analyzed the effects of the oblique incidence for the polarization modes TM and TE.
We propose a narrowband plasmonic absorber based on 3D fractal geometries. The geometric parameters of the proposed structure were optimized to exhibit strong absorption (above 90% for normal incidence) for transverse magnetic polarization in the region of electromagnetic spectrum used in optical communications (1.0 - 2.0 μm). The proposed structure demonstrated that the resonant peaks can be tunned with the geometric parameters of the structure. We also analyzed the dependence of thickness and effects of fractal rotation to analyze fabrication tolerance.
We proposed a broadband absorber based in rectangular metallic and dielectric grating. The geometric parameters of the proposed structure were optimized to exhibits strong absorption (above 90% for incidence normal) with polarization-independent in the visible spectrum (400-700nm). The proposed structure has demonstrated wide-angle absorption of above 80% for angles of incidence of up to 60° for TM mode and up to 40° for TE mode. The high absorption does not change when we vary other geometric parameters of the structure to analyze the fabrication tolerance.
Plasmonic groove structures, which are widely known for its absorbent properties of light, are numerically investigated. Genetic algorithms have been successfully used to aid in the design of two-dimensional high efficiency wide-angle plasmonic groove absorbers for visible wavelengths. The novel periodic groove structure exhibits absorption above 90% for ultra-broadband wavelengths ranging from 300 to 700nm. The resonant modes induce localized zero wavevector plasmon polaritons in the metallic material which favors absorption and may also enhance non-linear optical processes.
We show that a planar metal-dielectric-metal structure has a resonant characteristic that can be used to filter specific colors of the visible spectrum depending of the choice of the material used in the dielectric layer. The resonance occurs when the reflection phase is canceled out with the phase of the propagation. We numerically demonstrate a structure that can be used as an RGB optical filter with three different dielectric materials, with transmission of above 60%. The planar structure exhibits wide-angle transmission for angles of incidence up to 50° for the red and blue colors and up to 30° for the green color.
We proposed and designed angle insensitive color filter based in metal/dielectric multilayers structures for red electromagnetic radiation (620-750nm). The thickness of the dielectric in the structure is calculated according to the physical theory and the omnidirectional resonance occurs when the reflection phase shift cancels the propagation displacement. The thickness of the metal is chosen analyzing a transmission properties in an interval of thicknesses previously described in the literature. We obtain analytically a highly stable filter with a transmission peak greater than 70% in approximately 634nm. This device can keep the same perceived transmitted color when the incidence angle changes from 0° to 50°, especially for TM polarized light.
A multipeak polarization independent absorber based on ultrathin metamaterials composed of metal layers (Al) and dielectric (polymer, ZnSe) has been proposed and numerically analyzed. The absorber is composed by a trapezoidal shaped grating filled by a polymer. This structure possess resonant absorption modes at multi-frequencies. Numerical results show that near unity absorption peaks can be obtained for both polarization modes (TM and TE) for visible radiation at normal incidence.
We present a broadband absorber with the half-cylinder geometry composed of thin film with metallic / dielectric
multilayers. The geometric and physical parameters of the proposed structure were optimized to obtain an average
absorption above 90% for the modes of electric polarization (TE) and magnetic (TM) in the visible spectrum. High
absorption is observed for incident angles of up to 40 degrees in TE mode and 80 degrees for TM mode. The effects
of structure periodicity are also investigated for both modes and the results show small changes over a range of 200
nm . In medium IR (infrared) the structure can be scalable to obtain absorption peaks from its geometry.
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